Automating Downstream Injection Molding Processes Provides Competitive Advantages

Automated work cells and robots are commonly used in injection molding processes for tasks such as part extraction, insert molding, over-molding, and in-mold labeling. However, there are many often overlooked downstream applications offering just as many benefits for injection molders who are looking to increase efficiency, quality and throughput while reducing costs.

Automation in Injection Molding Processes

Injection molding is typically used in the mass production of identical parts and products because it allows efficiency in large quantities. However, many of the steps require intervention from workers and these activities are often repetitive, labor intensive and require exacting precision. As demand for high-volume plastics began to increase, automation was added to injection molding lines to relieve workers of these tasks. As a result of automating these operations, plastic manufacturers have been able to reduce injuries among staff, boost throughput and improve consistency and quality of products.

Many of the traditionally automated upstream tasks involve:

  • Unloading of finished parts from the machine.
  • Insert loading, the process of encapsulating an insert, such as a pin, blade, or rod, in molded plastic.
  • Over-molding, where two or more separately molded parts are combined to produce one part.
  • In-mold labeling, which includes decorating or labeling plastic injection molded parts during the injection molding process.

Automated Downstream Injection Molding Applications

Thanks to technological advances in automation, robotics, vision systems and end of arm tooling, automation is available for many post-process injection molding applications, as well. Some downstream applications that will provide gains in efficiency, speed and quality include:

Machine tending of finished partsPick and PlaceTrimming and clipping
Robots can be used to pick up finished parts, place them into CNC machines, close the door, then start the machine. Once the machining is complete, the robot can remove the part and start the cycle again.Robots can pick and place finished parts and products that are destined for further assembly, packaging, and printing processes.Automated work cells can be designed so that a robot can pick up an ejected part from a mold and trim or clip excess material.
RecyclingAssemblyHot stamping
Following the injection molding process there are typically solid plastic sprues and runners that can be collected by robots and placed into the granulator for recycling and reuse in the process.Robots can perform the complex operations needed to assemble the injection molded parts into finished plastic products. Robots can also be relied on to dispense adhesive and sealants in a precise and repeatable pattern on finished pieces as part of an assembly line.Automated cells can be created for picking up finished parts and performing hot stamping tasks with increased speed, safety, and repeatability.
Testing and inspectionAutomated finishingWrapping, packaging, and palletizing
Robotic automation equipped with machine vision can be employed to pick up, test and inspect finished parts and products to ensure quality and consistency. They can relocate any parts that do not meet quality standards to a reject bin for recycling.Robotic cells can be employed downstream to print or polish the finished injection molded parts or products. They can also apply labels to finished products.Automation can be applied to ensure efficiency, speed, consistency, and accuracy during these end-of-the-line procedures.

The Benefits of Automating Injection Molding Processes

There are many benefits to automating both the upstream and downstream operations of the injection molding process, including:

Reduced labor costsLabor costs are extremely high for injection molders and workers are becoming harder to find and retain. Automation helps offset or reduce the costs by replacing human workers, which also boosts efficiency and throughput, improves quality, and reduces safety risks to human workers while redirecting them to other, more complex tasks to maximize the value of the existing workforce.
Increased throughputWhen used through both upstream and downstream injection molding operations, automation intensifies and increases efficiency because it is so much faster and more accurate than manual labor. This allows injection molders to significantly increase throughput.
Faster lead timesThe ability to increase throughput coupled with the ability to run upstream and downstream processes 24/7 allows injection molders to accommodate faster lead times, which provides a worthwhile competitive advantage.
Higher quality partsThanks to the accuracy and precision of automation, there are fewer mistakes and less scrap/waste/rework involved in the process. The consistency and repeatability provided by automation means that the part is processed in the same way every time, which further ensures high quality parts and greater customer satisfaction.
Reduced wasteAgain, the accuracy and consistency provided by automation means that there will be less scrap and waste associated with bad parts. This is a high-value benefit for injection molders. In addition, robots can be used to collect runners and place them for recycling, which ensures that scrap is reused in the process, increasing material savings as well.

Technological advances in automation, robots, vision systems and end of arm tooling are allowing the use of automation in both upstream and downstream injection molding processes. Employing automation for the molding process, as well as post-processing operations, boosts efficiency, throughput, and quality, while reducing scrap and labor costs, giving savvy injection molders a significant competitive advantage. For more information on automating your injection molding application, please contact our DevLinks division.